Reduced umbilical artery prostacyclin formation in complicated pregnancies

Prostacyclin synthesis is severely depressed in the umbilical arteries of neonates of mothers with gestational diabetes mellitus, juvenile-onset diabetes mellitus, or preeclamptic symptoms, and of mothers who smoke during pregnancy and diabetic mothers who smoke. The reduced production of prostacyclin might be responsible for an increased abortion rate and a higher rate of intrauterine fetal death because of a decrease in placental perfusion and umbilical blood flow.     

Antenatal sonographic diagnosis of single umbilical artery

Seven fetuses with a single umbilical artery were detected at the perinatal ultrasound unit of Yale University during a one-year period. Other sonographic abnormalities included hydramnios (four cases) and intrauterine growth retardation (two cases). Two neonates died shortly after birth, two others survived with abnormalities, and three were normal. The varied sonographic appearances of single umbilical artery are illustrated and contrasted with sonograms of normal umbilical cords.     

Doppler umbilical artery velocimetry in pregnancies complicated by intrahepatic cholestasis.

Doppler umbilical velocimetry is a useful clinical tool for antepartum fetal surveillance of pregnancies at risk of fetal compromise. Intrahepatic cholestasis of pregnancy is associated with an increased incidence of fetal death, which might due to the toxic effect of elevated maternal serum concentrations of bile acids. To study a possible effect of the concentration of bile acids on the umbilical circulation we performed pulse-wave Doppler velocimetry of the umbilical artery in 15 patients with intrahepatic cholestasis between 34 and 38 weeks of gestation. The findings were compared to the Doppler flow velocities of the umbilical artery of 129 normal pregnancies. Peak-systolic (A) and end-diastolic (B) velocities of two to three cardiac cycles were measured by electronic calipers and the Pourcelot (PR)-index (PR = (A - B)(A)) was calculated. Two of 29 Doppler measurements in patients with intrahepatic cholestasis were above two standard deviations (2 SD) of the values in normal pregnancies. No significant correlation was found between Doppler flow velocities and serum levels of bile acids (r = 0.20) or the levels of alanine aminotransferase (ALAT) (r = -0.05). The mean level of bile acids was 24 mumol/l with a maximum of 98 mumol/l. The mean level of ALAT was 165 IU/l with a maximum of 576 IU/l. Since even high levels of bile acids do not influence umbilical circulation, Doppler investigations of the umbilical artery seem to be of little value in studying the disease-specific risk of fetal compromise in pregnancies complicated by intrahepatic cholestasis.     

The impact of different sides of the absent umbilical artery on fetal growth in an isolated single umbilical artery

Purpose

The aim of this study was to determine whether laterality of an absent umbilical artery (AUA) is associated with fetal growth in fetuses with isolated single umbilical artery (SUA).

Methods

Fifty singleton pregnancies were studied, including 26 cases with a right AUA and 24 cases with a left AUA in isolated SUA, and 200 singleton pregnancies with a three-vessel cord. Delivery data, including gestational age and birth weight and height, were recorded. Compare the birth weight and height in fetuses between the different sides of an AUA and the three-vessel cord by covariance analysis.

Results

The mean difference was 0.25 kg (SD 0.05; P < 0.05) in birth weight between fetuses with a left AUA and a three-vessel cord. The mean difference was 1.03 cm (SD 0.56; P < 0.05) in birth height between fetuses with a left AUA and a three-vessel cord. No significant differences were observed in birth weight and height between fetuses with a right AUA and those with a three-vessel cord.

Conclusion

Our data suggest that the birth weight and height of fetuses with a left AUA in isolated SUA are lower than those with a three-vessel cord.     

Antenatal sonographic detection of single umbilical artery.

The absence of one umbilical artery of single umbilical artery (SUA) is one of the most common congenital malformations in man. This vascular anomaly of the umbilical cord is frequently associated with other congenital malformations as well as some adverse perinatal events such as intrauterine growth retardation (IUGR), premature delivery, and increased perinatal mortality. Five cases of SUA detected prenatally by ultrasound are reported here in detail, including the first reported case in a twin gestation. None of the 5 affected infants had associated anomalies, but 2 cases of intrauterine growth retardation (IUGR) and 1 stillborn infant were noted in this series. An umbilical vein/umbilical artery ratio less than 2 was invariably found in all cases, making this observation another useful sonographic characteristic to use in the antenatal detection of SUA. Since the umbilical cord can be easily seen prenatally by ultrasound, and SUA is recognized as an important index for detecting congenital malformations, examination of the umbilical cord for the absence of one umbilical artery is an extremely valuable tool in prenatal diagnosis. The prenatal detection of SUA demands an extensive search for associated anomalies and a close surveillance of fetal well-being, since these fetuses have a high risk of fetal death or IUGR. Sonologists and sonographers should be aware of the possibility of SUA, especially in those cases associated with congenital malformations or IUGR.     

Pregnancy outcome in isolated single umbilical artery

Our objective was to determine whether the rate of small for gestational age (SGA) infants and adverse perinatal outcome are increased in pregnancies diagnosed with an isolated single umbilical artery (SUA). We compared 297 pregnancies with a SUA diagnosed on routine obstetrical ultrasound with 297 pregnancies with a three-vessel cord control. Pregnancies complicated by major fetal anomalies were excluded. The rate of SGA, fetal death, and neonatal outcomes were compared between the two groups. Data analysis were performed using the T-test and chi-square test. The sample size had 80% power to detect a 50% difference between groups assuming a SGA rate of 20% in the SUA group and 10% in the control, alpha = 0.05. Among the SUA group, in 21 neonates (7.1%) the presence of a SUA could not be confirmed by postnatal examination, and 21 (7.1%) had major congenital anomalies, leaving 255 for final analysis. In the control group, 8 of the 297 (2.7%) had major congenital anomalies, leaving 289 for final analysis. The incidence of SGA neonates was 35 of 255 (13.7%) in the isolated SUA group compared with 38 of 289 (13.1%) in the control group ( P = 0.93). The composite perinatal outcomes (fetal death and/or SGA) were also similar between the groups (16.1% versus 14.5%; P = 0.72). We concluded that pregnancies with isolated SUA have a similar rate of SGA to those with 3VC.When a SUA is identified antenatally, a targeted ultrasound is warranted to rule out associated anomalies. Serial antepartum ultrasound for fetal growth is not necessary in managing pregnancies complicated by isolated SUA.     

Maternal and umbilical cord copeptin levels in pregnancies complicated by fetal growth restriction

Objective: The aim of this study was to compare maternal and fetal serum copeptin concentrations in pregnancies complicated by isolated fetal growth restriction (FGR), and uncomplicated pregnancies, and to investigate relationships between copeptin levels and clinical parameters.

Methods: Maternal and fetal serum copeptin levels were measured in 21 women with pregnancies complicated by isolated FGR and 20 women with normal pregnancies (control group). Doppler assessment of the uterine and umbilical arteries was performed in each patient.

Results: Maternal serum copeptin levels were significantly higher in women with isolated FGR compared to controls (p?=?0.042). In addition, maternal copeptin levels were inversely correlated with the uterine artery pulsatility and resistance indices and positively correlated with neonatal birth weight. Umbilical vein copeptin levels were significantly increased in neonates with adverse outcomes (p?=?0.001).

Conclusions: Increased maternal copeptin concentration may reflect a response to stress, thus serving as a compensatory mechanism in pregnancies complicated by FGR.     

Perinatal outcomes in singleton pregnancies with a single umbilical artery

Objective: To analyze perinatal outcomes in singleton pregnancies with a single umbilical artery (SUA) as an isolated finding with no other underlying disorders.

Methods: This retrospective observational study compared a group of pregnancies with SUA (n?=?127) and a group with a normal 3-vessel umbilical cord (n?=?27?752). The study variables comprised maternal and obstetric characteristics and perinatal outcomes.

Results: The frequency of SUA was 0.45%. Pregnancies with SUA ended more frequently with cesarean delivery, and had a higher risk that the indication for cesarean delivery was non-reassuring fetal heart rate (NRFHR). Neonates in the SUA group had a lower weight for gestational age, and a higher risk of low umbilical cord blood pH.

Conclusion: Obstetricians should monitor fetal growth closely in pregnancies with SUA, and be alert to NRFHR during labor and delivery.     

Doppler velocimetry of the umbilical artery in pregnancies complicated by insulin-dependent diabetes mellitus.

The purpose of this study was to investigate vascular resistance by Doppler ultrasound in the umbilical artery of insulin-dependent diabetics longitudinally over the course of pregnancy. Special interest was put on the effects of glycemic control and maternal vascular disease on the flow velocity waveform (FVW) and the predictive value of Doppler flow measurements with regard to perinatal morbidity. Using a duplex-pulsed wave scanner, the resistance-index (PR index) in the umbilical artery was calculated. The mean value of a 24-h blood glucose profile and the concentration of glycosylated hemoglobin (HBA1C) were used as parameters of metabolic control. 53 pregnant diabetic women were examined longitudinally during the course of pregnancy on average on three occasions (range: 1-7) between 17 weeks of gestation and delivery at 37.7 +/- 1.3 (mean +/- SD) weeks. To test the predictive value of Doppler flow velocimetry with regard to perinatal morbidity the results were compared to the FVWs measured in the umbilical arteries of 30 non-diabetic women with normal fetal outcome. Vascular resistance in the umbilical artery of the diabetics declined significantly during the course of pregnancy, with a mean PR index of 0.729 (SD 0.051) at 17 weeks and 0.603 (SD 0.083) at the end of pregnancy (P < 0.002). The majority of PR indices were within the range reported for normal pregnancy and measured in the non-diabetic women. Regression analysis showed no significant correlation between vascular resistance and mean blood glucose level (r = 0.1325) or concentration of HBA1C (r = -0.0519). Maternal vascular disease had no effect on umbilical FVWs.(ABSTRACT TRUNCATED AT 250 WORDS)     

Flow-velocity profiles of the fetal aorta and umbilical artery in pregnancies complicated by pregnancy-induced hypertension and fetal growth retardation

Sixty-seven women undergoing ultrasonographic evaluation in the high-risk clinic were randomly recruited to be examined by a newly developed computerized method that presents flow-velocity profiles derived from pulsed Doppler-generated flow-velocity waveforms. Each woman had pulsed Doppler flow velocimetry of the fetal aorta and umbilical arteries done. Subjects were either normal controls (N = 20) or had pregnancies complicated by pregnancy-induced hypertension (N = 29), fetal growth retardation (N = 11), or both (N = 7). Distinct patterns of flow-velocity distribution across the fetal aorta and proximal umbilical arteries were identified in the pregnancies characterized by increased placental resistance. At peak systole, normal velocity was maintained only at a narrow area around the center of the vessel, whereas velocity in the rest of the vessel area was markedly reduced. These changes were present in 40 of 47 subjects (85.1%) with complicated pregnancies, whereas 27 of 47 (57.4%) had umbilical artery systolic-diastolic ratios above the 95th percentile. No significant differences between normal and complicated pregnancies were seen during diastole. Our findings suggest that increased placental resistance results in a redistribution of velocities within fetal blood vessels, often before maximal end-diastolic velocity is decreased.     

The association of single umbilical artery with cytogenetically abnormal pregnancies

The clinical significance of the absence of one of the two umbilical arteries (single umbilical artery) lies in its association with congenital malformations. Whether this association includes cytogenetic abnormalities is less clear. A retrospective review of all detected chromosomally abnormal pregnancies at the University of Maryland was carried out. Of 109 cytogenetically abnormal pregnancies, the number of umbilical cord vessels could be documented in 53 cases. Six (11.3%) had a single umbilical artery. A single umbilical artery was noted in two of nine fetuses (22.2%) with trisomy 18 and in two of six fetuses (33.3%) with trisomy 13. Two other unusual chromosomal constitutions were noted in cases of a single umbilical artery. None of the 11 fetuses with sex chromosome abnormalities (including eight with monosomy X) had a single umbilical artery. Of 18 fetuses with trisomy 21, none had a single umbilical artery. This study suggests that a single umbilical artery is preferentially associated with certain karyotypic abnormalities and that trisomy 21 does not appear to be associated with a single umbilical artery.     

Predictive values of umbilical artery waveforms and repeat cardiotocography in pregnancies complicated by nonreactive cardiotocography

Fifty patients with a nonreactive nonstress cardiotocograph were studied. All had measurement of the A/B ratio of the umbilical artery Doppler waveform and 39 also had a repeat nonstress test. The positive and negative predictive values of the repeat nonstress test were 61% and 94%, respectively, and those of the A/B ratio were 67% and 83%. A repeat nonreactive nonstressed cardiotocograph appeared to be a test of high sensitivity (92%) and the A/B ratio a test of high specificity (83%). It is suggested that the combination of the two tests may prove a powerful predictor of adverse perinatal outcome.     

Doppler assessment of umbilical artery, thoracic aorta and middle cerebral artery in the management of pregnancies with growth restriction

BACKGROUND: The aim of the study was to determine the best use of information obtained from Doppler studies of umbilical artery, thoracic aorta and middle cerebral artery in the management of pregnancies with growth restriction. METHODS: The study group consisted of 100 pregnant women with intrauterine growth restricted fetuses. Doppler flow velocity waveforms were obtained from the umbilical artery, middle cerebral artery and thoracic aorta. The pregnancies were grouped according to the umbilical artery Doppler results. There were 29, 30 and 41 fetuses with normal and high PI (pulsatility index), and absent end-diastolic velocity (AEDV) in the umbilical artery, respectively. RESULTS: Birth weight and umbilical vein pH at birth significantly decreased and perinatal mortality rates significantly increased with the worsening of the diastolic flow in the umbilical artery (p<0.01). Increased umbilical artery PI was significantly associated with increased thoracic aorta PI and decreased middle cerebral artery PI (r=0.75 and -0.55, p<0.01 respectively). Perinatal mortality due to fetal asphyxia in fetuses with AEDV in the umbilical artery and in both the umbilical artery and thoracic aorta was 39.5% and 50%, respectively. Detection of AEDV in the thoracic aorta was found to be the most significant predictive factor of perinatal deaths. CONCLUSIONS: The degree of abnormality of the Doppler findings parallels the severity of fetal compromise. Growth restricted fetuses with AEDV detected both in the umbilical artery and thoracic aorta are severely compromised and time gained in utero has no benefit for these fetuses.     

Umbilical artery Doppler velocimetry in pregnancies complicated by oligohydramnios

OBJECTIVE: To determine the role of umbilical artery Doppler velocimetry in the management of oligohydramnios. STUDY DESIGN: In a retrospective chart review covering a two-year period, pregnancies with oligohydramnios evaluated by Doppler velocimetry of the umbilical artery were identified. Those patients with ruptured membranes and complex congenital anomalies were excluded from analysis. In the remainder, various measures of perinatal morbidity, including delivery of a small-for-gestational-age infant, preterm delivery, hyperbilirubinemia, requirement for blood transfusion, and other cardiovascular or pulmonary complications, were correlated with recorded values of the systolic/diastolic (S/D) ratio. RESULTS: Seventy-six subjects were identified for study. Forty-six had normal S/D ratios; 17 (37%) were associated with identifiable perinatal morbidity. When prematurity due to delivery for the sole indication of oligohydramnios was excluded, morbidity occurred in five patients (11%). Conversely, of the 30 patients with abnormal Doppler indices, 80% had an adverse outcome. CONCLUSION: Pregnancies with oligohydramnios and normal umbilical artery Doppler velocimetry were significantly (P < .001) less likely to experience an abnormal perinatal outcome as compared to those with abnormal Doppler indices. An elevated S/D ratio identified an increased risk of an adverse perinatal outcome in women with oligohydramnios. Avoiding intervention in pregnancies with oligohydramnios and normal umbilical artery Doppler velocimetry may decrease iatrogenic morbidity due to prematurity by as much as 26%.     

Umbilical artery blood flows among pregnancies with single umbilical artery: a prospective case-control study

Objectives: To evaluate peak systolic velocity (PSV) in the umbilical artery (UA) among patients with single umbilical artery (SUA) as compared with patients with three vessel cords.

Methods: A prospective case-control study was performed. UA blood flow velocimetry was obtained from fetuses with SUA and from a control group with three vessel cord. PSV and pulsatility index (PI) were measured. Patients’ characteristics were compared for statistical differences and a linear regression model was constructed for the different groups.

Results: UA Doppler velocimetry measurements were obtained from 29 patients with SUA and from 29 controls matched for gestational age. The differences between UA PI with and without SUA were significant (F?=?3.471; p?=?0.0379) showing a lower PI in the SUA group. However, no significant statistical difference was found in PSV between these two groups (F?=?0.149; p?=?0.86).

Conclusions: While the impedance in the UA of patients with a SUA was lower compared with patients with a normal umbilical cord, the PSV did not differ.     

Fetal health assessment in pregnancies complicated by sickle hemoglobinopathies

The contraction stress test (CST) and nonstress test (NST) are used as fetal health assessments. Severe sickle hemoglobinopathies in the parturient have been shown to place the fetus significantly at risk. This study correlates these fetal health assessment tests with outcome data in 58 pregnancies occurring in women with sickle cell disease. There were 30 patients with homozygous sickle cell anemia (HbS-S), 19 with hemoglobin S-C disease (HbS-C), and nine with hemoglobin S-thalassemia (HbS-Thal). All received prophylactic partial exchange transfusions as part of their antepartal care. At 34 weeks' gestation, NSTs followed by CSTs were begun in each patient. A total of 255 tests were performed. Of these, 19 NSTs and 24 CSTs were unsatisfactory or questionably abnormal and were repeated. There were no nonreactive NSTs, and no patient demonstrated a positive CST. The neonatal outcome revealed one infant who was small for gestational age and two infants who were of low birth weight but appropriate for gestational age. All infants survived and were normal. These data suggest that the fetal reactivity and placental reserve among these parturients with severe sickle hemoglobinopathies were uncompromised, as these tests have been shown to be relatively sensitive assessments of fetal well-being in other maternal disorders.     

Placental abnormalities associated with isolated single umbilical artery in small-for-gestational-age births

BackgroundPrevious studies have shown that pregnancies complicated by placentas with an isolated single umbilical artery (iSUA) are at increased risk for small-for-gestational-age (SGA) births. The etiology of SGA in this population, however, remains unknown.ObjectiveThe primary objective of this study was to evaluate whether placental abnormalities in pregnancies with SGA births differ according to the presence of iSUA.Study designThis was an observational study of all women with pathologic examination of the placenta after delivering a non-anomalous, singleton SGA neonate between January 2009 and August 2015. SGA was defined as birthweight less than 10th percentile for gestational age. Women were categorized according to whether they had an iSUA or a three-vessel cord. The following placental pathologies were compared between the groups using bivariable and multivariable analyses: SGA placenta, maternal vascular malperfusion, high grade fetal vascular malperfusion, and chronic villitis.Results1833 women were included in the analysis: 34 with iSUA and 1799 with three-vessel cord. More than 85% of women in both groups had at least one placental abnormality. After adjusting for nulliparity and neonatal gender, the presence of iSUA was associated with increased odds of high grade fetal vascular malperfusion (adjusted odds ratio 2.8, 95% confidence interval 1.1–7.5) and decreased odds of maternal vascular malperfusion (adjusted odds ratio 0.2, 95% confidence interval 0.1–0.9). There was no significant association with other pathologic findings.ConclusionPathologic placental findings associated with SGA birth differed based on umbilical cord composition. The presence of iSUA in an SGA birth was associated with a higher odds of high grade fetal vascular malperfusion abnormalities and lower odds of maternal vascular malperfusion abnormalities, compared to SGA birth with a 3VC.     

Fetal cerebral and umbilical Doppler in pregnancies complicated by late-onset placental abruption

Objective: To evaluate whether changes in the cerebroplacental Doppler and birth weight (BW) suggestive of chronic fetal hypoxemia, precede the development of late-onset placental abruption (PA) after 32 weeks.

Methods: In a multicenter retrospective study, the Doppler examinations of the fetal umbilical artery (UA) and middle cerebral artery (MCA) recorded after 32 weeks were collected in pregnancies subsequently developing PA. The BW centiles were calculated and the MCA pulsatility indices (PI), and UA PI were converted into multiples of the median (MoM). Afterwards, a comparison was made with a group of fetuses, which did not develop PA. Logistic regression was used to adjust for potential confounders and evaluate the feasibility of the prediction model.

Results: Pregnancies complicated by late-onset PA (n?=?31) presented lower MCA PI (p?=?0.015) and were smaller (p?n?=?1294). Logistic regression analysis indicated that cerebral vasodilation was more important than umbilical flow in the explanation of PA (MCA PI OR?=?0.106, p?=?0.014 and UA PI OR 1.901, p?=?0.32). In addition, the influence of BW exerted was residual (BW centile OR?=?0.989, p?=?0.15).

Conclusions: Fetuses developing late-onset PA demonstrate significant cerebral vasodilation with scarce placental dysfunction, suggesting the existence of some kind of chronic hypoxemia that follows the late-onset pattern.     

Fetal growth in pregnancies complicated by placenta praevia]

Intrauterine growth of neonates born from 167 pregnancies complicated with placenta praevia has been analysed. Growth in 22,7% of the total neonates was retarded as compared to fetal age. About half of these newborns died (18 out of 38). The authors draw the attention prematures with retarded growth. The total perinatal mortality amounted to 25,7% (purified percentage: 23,5). The placental coefficient value was consistently higher than the values obtained in normal pregnancies. This may be explained with the disturbed function of the placenta owing to its abnormal adherence. The retarded growth of the fetus seems to play an important role in the still high perinatal mortality rate of neonates born from pregnancies complicated with placenta praevia.